Sam Altman-led OpenAI's o3 defeated Elon Musk-owned xAI's Grok 4 during AI Chess Exhibition Tournament 2025 after winning 4-0. Reacting to a move by Grok 4 during its match with o3, world number one chess player Magnus Carlsen said, "There's always that one guy...who's learnt theory and literally knows nothing else." o3 defeated o4 mini and Kimi K2 instruct too.